Teams that care about getting at large bids to NCAA will try to play a tougher schedule, teams that don't think they have a shot outside of winning their conference with an automatic bid, may or may not schedule tougher teams. All depends on coaches philosophy of preparing for conference by winning or playing hard teams.
Region matters as to what your competition can be, as well as which spring trip you take, some organized areas like RussMatt and Ripkin etc. schedule your games based on your past records, so often you just end up playing competition at or below your level (particularly D3).
Strength of schedule is pretty important for those constant second and third place teams in the conference.